/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the  "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/*
 * $Id$
 */
package wx.xml.xalan.xalan.templates;

import org.xml.sax.SAXException;

import javax.xml.transform.TransformerException;

import wx.xml.xalan.xalan.res.XSLTErrorResources;
import wx.xml.xalan.xalan.transformer.TransformerImpl;
import wx.xml.xalan.xml.serializer.SerializationHandler;
import wx.xml.xalan.xml.utils.QName;
import wx.xml.xalan.xml.utils.XML11Char;
import wx.xml.xalan.xpath.XPathContext;

/**
 * Implement xsl:element
 * <pre>
 * <!ELEMENT xsl:element %template;>
 * <!ATTLIST xsl:element
 *   name %avt; #REQUIRED
 *   namespace %avt; #IMPLIED
 *   use-attribute-sets %qnames; #IMPLIED
 *   %space-att;
 * >
 * </pre>
 *
 * @xsl.usage advanced
 * @see <a href="http://www.w3.org/TR/xslt#section-Creating-Elements-with-xsl:element">XXX in XSLT Specification</a>
 */
public class ElemElement extends ElemUse {
    static final long serialVersionUID = -324619535592435183L;

    /**
     * The name attribute is interpreted as an attribute value template.
     * It is an error if the string that results from instantiating the
     * attribute value template is not a QName.
     *
     * @serial
     */
    protected AVT m_name_avt = null;
    /**
     * If the namespace attribute is present, then it also is interpreted
     * as an attribute value template. The string that results from
     * instantiating the attribute value template should be a URI reference.
     * It is not an error if the string is not a syntactically legal URI reference.
     *
     * @serial
     */
    protected AVT m_namespace_avt = null;

    /**
     * Get the "name" attribute.
     * The name attribute is interpreted as an attribute value template.
     * It is an error if the string that results from instantiating the
     * attribute value template is not a QName.
     *
     * @return Name attribute for this element
     */
    public AVT getName() {
        return m_name_avt;
    }

    /**
     * Set the "name" attribute.
     * The name attribute is interpreted as an attribute value template.
     * It is an error if the string that results from instantiating the
     * attribute value template is not a QName.
     *
     * @param v Name attribute to set for this element
     */
    public void setName(AVT v) {
        m_name_avt = v;
    }

    /**
     * Get the "namespace" attribute.
     * If the namespace attribute is present, then it also is interpreted
     * as an attribute value template. The string that results from
     * instantiating the attribute value template should be a URI reference.
     * It is not an error if the string is not a syntactically legal URI reference.
     *
     * @return Namespace attribute for this element
     */
    public AVT getNamespace() {
        return m_namespace_avt;
    }

    /**
     * Set the "namespace" attribute.
     * If the namespace attribute is present, then it also is interpreted
     * as an attribute value template. The string that results from
     * instantiating the attribute value template should be a URI reference.
     * It is not an error if the string is not a syntactically legal URI reference.
     *
     * @param v NameSpace attribute to set for this element
     */
    public void setNamespace(AVT v) {
        m_namespace_avt = v;
    }

    /**
     * This function is called after everything else has been
     * recomposed, and allows the template to set remaining
     * values that may be based on some other property that
     * depends on recomposition.
     */
    public void compose(StylesheetRoot sroot) throws TransformerException {
        super.compose(sroot);

        StylesheetRoot.ComposeState cstate = sroot.getComposeState();
        java.util.Vector            vnames = cstate.getVariableNames();
        if (null != m_name_avt)
            m_name_avt.fixupVariables(vnames, cstate.getGlobalsSize());
        if (null != m_namespace_avt)
            m_namespace_avt.fixupVariables(vnames, cstate.getGlobalsSize());
    }


    /**
     * Get an int constant identifying the type of element.
     *
     * @return The token ID for this element
     * @see wx.xml.xalan.xalan.templates.Constants
     */
    public int getXSLToken() {
        return Constants.ELEMNAME_ELEMENT;
    }

    /**
     * Return the node name.
     *
     * @return This element's name
     */
    public String getNodeName() {
        return Constants.ELEMNAME_ELEMENT_STRING;
    }

    /**
     * Resolve the namespace into a prefix.  Meant to be
     * overidded by elemAttribute if this class is derived.
     *
     * @param rhandler      The current result tree handler.
     * @param prefix        The probable prefix if already known.
     * @param nodeNamespace The namespace.
     * @return The prefix to be used.
     */
    protected String resolvePrefix(SerializationHandler rhandler,
                                   String prefix, String nodeNamespace)
        throws TransformerException {

//    if (null != prefix && prefix.length() == 0)
//    {
//      String foundPrefix = rhandler.getPrefix(nodeNamespace);
//
//      // System.out.println("nsPrefix: "+nsPrefix);           
//      if (null == foundPrefix)
//        foundPrefix = "";
//    }
        return prefix;
    }

    /**
     * Create an element in the result tree.
     * The xsl:element element allows an element to be created with a
     * computed name. The expanded-name of the element to be created
     * is specified by a required name attribute and an optional namespace
     * attribute. The content of the xsl:element element is a template
     * for the attributes and children of the created element.
     *
     * @param transformer non-null reference to the the current transform-time state.
     * @throws TransformerException
     */
    public void execute(
        TransformerImpl transformer)
        throws TransformerException {

        if (transformer.getDebug())
            transformer.getTraceManager().fireTraceEvent(this);

        SerializationHandler rhandler   = transformer.getSerializationHandler();
        XPathContext         xctxt      = transformer.getXPathContext();
        int                  sourceNode = xctxt.getCurrentNode();


        String nodeName = m_name_avt == null ? null : m_name_avt.evaluate(xctxt, sourceNode, this);

        String prefix        = null;
        String nodeNamespace = "";

        // Only validate if an AVT was used.
        if ((nodeName != null) && (!m_name_avt.isSimple()) && (!XML11Char.isXML11ValidQName(nodeName))) {
            transformer.getMsgMgr().warn(
                this, XSLTErrorResources.WG_ILLEGAL_ATTRIBUTE_VALUE,
                new Object[]{Constants.ATTRNAME_NAME, nodeName});

            nodeName = null;
        } else if (nodeName != null) {
            prefix = QName.getPrefixPart(nodeName);

            if (null != m_namespace_avt) {
                nodeNamespace = m_namespace_avt.evaluate(xctxt, sourceNode, this);
                if (null == nodeNamespace ||
                    (prefix != null && prefix.length() > 0 && nodeNamespace.length() == 0))
                    transformer.getMsgMgr().error(
                        this, XSLTErrorResources.ER_NULL_URI_NAMESPACE);
                else {
                    // Determine the actual prefix that we will use for this nodeNamespace

                    prefix = resolvePrefix(rhandler, prefix, nodeNamespace);
                    if (null == prefix)
                        prefix = "";

                    if (prefix.length() > 0)
                        nodeName = (prefix + ":" + QName.getLocalPart(nodeName));
                    else
                        nodeName = QName.getLocalPart(nodeName);
                }
            }

            // No namespace attribute was supplied. Use the namespace declarations
            // currently in effect for the xsl:element element.
            else {
                try {
                    // Maybe temporary, until I get this worked out.  test: axes59
                    nodeNamespace = getNamespaceForPrefix(prefix);

                    // If we get back a null nodeNamespace, that means that this prefix could
                    // not be found in the table.  This is okay only for a default namespace
                    // that has never been declared.

                    if ((null == nodeNamespace) && (prefix.length() == 0))
                        nodeNamespace = "";
                    else if (null == nodeNamespace) {
                        transformer.getMsgMgr().warn(
                            this, XSLTErrorResources.WG_COULD_NOT_RESOLVE_PREFIX,
                            new Object[]{prefix});

                        nodeName = null;
                    }

                } catch (Exception ex) {
                    transformer.getMsgMgr().warn(
                        this, XSLTErrorResources.WG_COULD_NOT_RESOLVE_PREFIX,
                        new Object[]{prefix});

                    nodeName = null;
                }
            }
        }

        constructNode(nodeName, prefix, nodeNamespace, transformer);

        if (transformer.getDebug())
            transformer.getTraceManager().fireTraceEndEvent(this);
    }

    /**
     * Construct a node in the result tree.  This method is overloaded by
     * xsl:attribute. At this class level, this method creates an element.
     * If the node is null, we instantiate only the content of the node in accordance
     * with section 7.1.2 of the XSLT 1.0 Recommendation.
     *
     * @param nodeName      The name of the node, which may be <code>null</code>.  If <code>null</code>,
     *                      only the non-attribute children of this node will be processed.
     * @param prefix        The prefix for the namespace, which may be <code>null</code>.
     *                      If not <code>null</code>, this prefix will be mapped and unmapped.
     * @param nodeNamespace The namespace of the node, which may be not be <code>null</code>.
     * @param transformer   non-null reference to the the current transform-time state.
     * @throws TransformerException
     */
    void constructNode(
        String nodeName, String prefix, String nodeNamespace, TransformerImpl transformer)
        throws TransformerException {

        boolean shouldAddAttrs;

        try {
            SerializationHandler rhandler = transformer.getResultTreeHandler();

            if (null == nodeName) {
                shouldAddAttrs = false;
            } else {
                if (null != prefix) {
                    rhandler.startPrefixMapping(prefix, nodeNamespace, true);
                }

                rhandler.startElement(nodeNamespace, QName.getLocalPart(nodeName),
                    nodeName);

                super.execute(transformer);

                shouldAddAttrs = true;
            }

            transformer.executeChildTemplates(this, shouldAddAttrs);

            // Now end the element if name was valid
            if (null != nodeName) {
                rhandler.endElement(nodeNamespace, QName.getLocalPart(nodeName),
                    nodeName);
                if (null != prefix) {
                    rhandler.endPrefixMapping(prefix);
                }
            }
        } catch (SAXException se) {
            throw new TransformerException(se);
        }
    }

    /**
     * Call the children visitors.
     *
     * @param visitor The visitor whose appropriate method will be called.
     */
    protected void callChildVisitors(XSLTVisitor visitor, boolean callAttrs) {
        if (callAttrs) {
            if (null != m_name_avt)
                m_name_avt.callVisitors(visitor);

            if (null != m_namespace_avt)
                m_namespace_avt.callVisitors(visitor);
        }

        super.callChildVisitors(visitor, callAttrs);
    }

}
